1. Field of the Invention
The present invention relates to a composite lens such as an aspherical lens, a fresnel lens, an achromatic lens, a diffraction grating, etc., having an active energy ray-curing resin adhesively formed on a surface of a glass base material, a manufacturing method for the composite lens, and a lens module including the composite lens.
2. Description of Related Art
In recent years, a technique for adhesively forming an active energy ray-curing resin on a surface of a glass base material has been developed and utilized as a manufacturing method for an aspherical lens and the like (see JP 1-171932 A and JP 3-13902 A). However, in the case of formation of a resin on a glass base material surface, there has been a problem that residual stress inside the resin layer due to shrinkage during curing of the resin separates the resin layer from the glass base material or produces cracks in the resin layer in a completed product because of a temperature change in usage atmosphere.
Accordingly, there have been a method of curing a resin in two separate stages, and a method of first curing only a center portion of a resin using a mask and last curing the whole resin (see JP 2722623 B, and JP 3111677 B). However, the above methods have a problem that a production cost becomes higher due to increased processes.